An example of the conventional solenoid valve and valve opening-closing timing control device is shown in Japanese Unexamined Patent Application Publication No. 10-159519 (PTL 1).
The above conventional art relates to a valve opening-closing timing control device for changing and controlling the opening/closing timing for an intake or exhaust valve provided in a cylinder during operation of an internal combustion engine. Such a device includes a driving rotary element synchronously rotatable with a crankshaft, a driven rotary element disposed coaxially with and relatively rotatable with the driving rotary element to be rotatable in unison with a camshaft for opening and closing the intake or exhaust valve, and a lock element for engaging the driving rotary element with the driven rotary element to be rotatable in unison. The lock element can be released by hydraulic oil supplied to an advanced angle chamber or a retarded angle chamber formed between the driving rotary element and the driven rotary element when the internal combustion engine is started.
According to the conventional art, a pressure-discharging passage is provided for discharging pressure of one of the advanced angle chamber and the retarded angle chamber to which hydraulic pressure is applied first in order to prevent air mixed in oil from erroneously releasing the lock element before the hydraulic pressure starts to work sufficiently when the internal combustion engine is started.
As a result, even if air is mixed in oil before the hydraulic pressure starts to work sufficiently when the internal combustion engine is started, for example, the air is discharged through the pressure-discharging passage, thereby to avoid erroneous operation of the lock element for reliably preventing a vane from colliding with a wall of the advanced angle chamber or the retarded angle chamber and producing striking sound. Thus, according to the conventional arrangement, the pressure-discharging passage is provided in a side surface of the lock element for releasing the air. The pressure-discharging passage has a size for allowing only air to pass through the hydraulic chamber to the outside.